1. Field of the Invention
The invention relates generally to handheld electronic devices and, more particularly, to a handheld electronic device that enables a user to establish a prioritized list of preferred networks to be used in roaming situations. The invention also relates to an improved method of establishing a prioritized list of preferred networks to be used by a handheld electronic device in roaming situations.
2. Description of the Related Art
Numerous types of handheld electronic devices are known. Examples of such handheld electronic devices include, for instance, personal data assistants (PDAs), handheld computers, two-way pagers, cellular telephones, and the like. Such handheld electronic devices are generally intended to be portable and thus are relatively small.
Many handheld electronic devices include and provide access to a wide range of integrated applications, including, without limitation, email, telephone, short message service (SMS), multimedia messaging service (MMS), browser, calendar and address book applications, such that a user can easily manage information and communications from a single, integrated device. These applications are typically selectively accessible and executable through a user interface that allows a user to easily navigate among and within these applications.
Many handheld electronic devices include wireless telephone and data (e.g., email, SMS, Internet) functionality. As is known in the art, wireless services, such as telephone and data services, are provided by way of an air interface involving radio frequency (RF) communications between wireless enabled equipment, such as a handheld electronic device described above, and one or more networks of land based radio transmitters or base stations. Each such network is commonly referred to as a public land mobile network (PLMN). PLMNs interconnect with other PLMNs and the public switched telephone network (PSTN) for telephone communications or with Internet service providers for data and Internet access.
In order to use wireless communications functionality, a user must subscribe with a wireless service provider or operator. The subscription permits the user to utilize the PLMN operated by the service provider or operator (referred to as the “home PLMN”). As is known in the art, roaming is a service offered by PLMN operators which allows a subscriber to use his or her wireless enabled equipment while in the service area of another operator (and outside of the user's home PLMN). Roaming requires an agreement between operators of technologically compatible systems to permit customers of either operator to access the other's PLMN. Service providers or operators typically charge a higher per-minute fee for calls placed outside their home calling or coverage area (the area serviced by their PLMN).
As is also known in the art, devices, such as handheld electronic devices, that include wireless functionality, such as telephone and data functionality, are provided with a subscriber identity module card (SIM card). A SIM card is a small printed circuit board that contains subscriber details, including data that identifies the user to the service provider, security information, and memory for a personal directory of numbers. In addition, the SIM card stores a pre-set, prioritized list of particular PLMNs to be used by the device in roaming situations. The particular PLMNs included in the list are normally based on the marketing preferences of a particular operator. However, as will be appreciated, different PLMNs have differing charges associated with them and offer different levels of reliability and service quality. Thus, a user may desire to use PLMNs other than those pre-stored in the SIM card and/or use PLMNs in a different order of priority than that specified in the SIM card based on issues of cost, reliability, and service quality, among others. Thus, there is a need for an improved handheld electronic device that enables a user to establish a prioritized list of preferred PLMNs to be used in roaming situations.